Inflammation represents a key event of many diseases, such as psoriasis, inflammatory bowel diseases, rheumatoid arthritis, asthma, multiple sclerosis, atherosclerosis, cystic fibrosis, and sepsis. Inflammatory cells, such as neutrophils, eosinophils, basophils, mast cells, macrophages, endothelial cells, and platelets, respond to inflammatory stimuli and foreign substances by producing bioactive mediators. These mediators act as autocrines and paracrines by interacting with many cell types to promote the inflammatory response. There are many mediators that can promote inflammation, such as cytokines and their receptors, adhesion molecules and their receptors, antigens involved in lymphocyte activation, and IgE and its receptors.
Cytokines, for example, are soluble proteins that allow for communication between cells and the external environment. The term cytokines includes a wide range of proteins, such as lymphokines, monokines, interleukins, colony stimulating factors, interferons, tumor necrosis factors, and chemokines. Cytokines serve many functions, including controlling cell growth, migration, development, and differentiation, and mediating and regulating immunity, inflammation, and hematopoiesis. Even within a given function, cytokines can have diverse roles. For example, in the context of mediating and regulating inflammation, some cytokines inhibit the inflammatory response (anti-inflammatory cytokines), others promote the inflammatory response (pro-inflammatory cytokines). And certain cytokines fall into both categories, i.e., can inhibit or promote inflammation, depending on the situation. The targeting of proinflammatory cytokines to suppress their natural function, such as with antibodies, is a well-established strategy for treating various inflammatory diseases.
TNFα (Tumor Necrosis Factor alpha) is a cytokine which promotes an inflammatory response and is involved in several inflammatory and autoimmune diseases or disorders. Binding TNFα has been proposed as a strategy for providing various diagnostic and therapeutic effects. For example, U.S. Pat. No. 5,075,236 teaches forming murine anti-TNFα antibodies by a hybridoma method. The anti-TNFα antibodies can be used in an assay to detect Kawasaki Disease.
A line of patents including U.S. Pat. No. 5,656,272, U.S. Pat. No. 5,919,452, and U.S. Pat. No. 6,790,444 relate to treating TNF-α-mediated diseases using an anti-TNFα antibody or peptide. The antibody is preferably a monoclonal chimeric antibody known as cA2. The A2 refers to a murine antibody that effectively binds human TNFα. The antigen binding region of A2 is combined with the constant region of a human IgG1 to make a chimeric antibody designated cA2. The diseases to be treated include rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, etc. The chimeric antibody cA2 has been commercialized under the name infliximab and is sold under the brand name REMICADE® (Centocor Ortho Biotech Inc).
U.S. Pat. No. 5,605,690 relates to a TNFα receptor polypeptide that binds TNFα. A recombinant chimeric antibody can be formed using the receptor sequence in place of the variable domain of the heavy and/or light chain. Human IgG1 is suggested for the constant regions. A chimeric antibody containing a combination of the TNFα receptor linked to an Fc portion of an IgG1 has been commercialized under the name etanercept, which is sold under the brand name ENBREL® (Immunex Corporation). Etanercept is approved to treat rheumatoid arthritis and plaque psoriasis.
U.S. Pat. No. 6,090,382 relates to human antibodies, or the antigen binding portions thereof, that bind human TNFα. The heavy chain constant regions of the human antibody can be IgG1, IgG2, IgG3, IgG4, IgA, IgE, IgM, or IgD and preferably is IgG1 or IgG4. The antibodies are taught to be useful in treating a variety of conditions including autoimmune (e.g., rheumatoid arthritis, multiple sclerosis) and intestinal disorders (e.g., Crohn's disease, IBD, ulcerative colitis). The preferred IgG1 antibody has been commercialized under the name adalimumab and is sold under the brand name HUMIRA® (Abbott Laboratories).
U.S. Pat. No. 7,012,135 and U.S. Pat. No. 7,186,820 relate to an antibody or fragment thereof that specifically binds TNFα wherein the variable domain region comprises specified CDR sequences. The constant region domains, when present, may be human IgA, IgD, IgE, IgG, or IgM domains, with IgG being preferred. A PEGylated modified Fab fragment has been commercialized as certolizumab pegol and sold under the brand name CIMZIA® (UCB Group of Companies) and is approved for treating rheumatoid arthritis and Crohn's disease.
Published U.S. application 2009/214528 shows the production of another anti-TNFα antibody known as golimumab and sold under the brand name SIMPONI® (Centocor Ortho Biotech Inc.). Golimumab is a fully human monoclonal antibody directed to TNFα. It is approved for treating rheumatoid arthritis.
The currently approved anti-TNFα antibodies are IgG-based. And these compounds are administered systemically to a patient via multiple injections or infusions (e.g., multiple intravenous or subcutaneous injections). See Reimund, J-M et al., Inflammation Allergy Drug Discovery 1, 21-34 (2007). These IgG-based anti-TNFα compounds, however, suffer from one or more undesirable effects. For example, it has been reported that REMICADE® infliximab; a chimeric IgG1κ monoclonal antibody specific for TNFα) is associated with hypersensitivity reactions in the patient, likely due to the non-human portions of the REMICADE® antibodies. Id. Similarly, it has been reported that patients taking HUMIRA® (adalimumab; a recombinant human IgG1 monoclonal antibody specific for human TNFα) developed an immune response against the HUMIRA® antibodies. Id. It has also been reported that patients taking CIMZIA® (certolizumab pegol; a recombinant humanized antibody Fab′ fragment with specificity for human TNFα conjugated to an approximately 40 kDa polyethylene glycol) developed an immune response against the CIMZIA® compound and reported mild to moderate adverse effects (most common being headache). Id. Alternatively, it has also been reported that the subcutaneous injection of ENBREL® (etanercept; a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human p75 TNF receptor linked to the Fc portion of human IgG1) was not shown to be better than placebos in treating Crohn's patients. Id.
Systemic depletion of TNFα furthermore increases the risk of the patient for infections, as indicated by black box warnings (as required by FDA for HUMIRA®, REMICADE®, SIMPONI® (golimumab; a human IgG1κ monoclonal antibody specific for human TNFα), and CIMZIA®) for increased risk of serious infections leading to hospitalization or death, including tuberculosis (TB), bacterial sepsis, invasive fungal infections (such as histoplasmosis), and infections due to other opportunistic pathogens.
In an attempt to reduce side effects associated with systemic treatment and to eliminate the inconvenience and expense of infusions, an article proposed an oral anti-TNF therapy that could be useful in treating Crohn's disease. Worledge et al. “Oral Administration of Avian Tumor Necrosis Factor Antibodies Effectively Treats Experimental Colitis in Rats.” Digestive Diseases and Sciences 45(12); 2298-2305 (December 2000). This article describes immunizing hens with recombinant human TNF and an adjuvant, fractionating polyclonal yolk antibody (IgY, which in chickens is the functional equivalent to IgG), and administering the unformulated polyclonal IgY (diluted in a carbonate buffer to minimize IgY acid hydrolysis in the stomach) to rats in an experimental rodent model of colitis. The rats were treated with 600 mg/kg/day of the polyclonal IgY. The uses of animal antibodies and polyclonal antibodies, however, are undesirable.
In a similar attempt to avoid adverse events associated with systemic administration, another group, Avaxia Biologics Inc., describes a topical (e.g., oral or rectal) animal-derived polyclonal anti-TNF composition that could be useful in treating inflammation of the digestive tract, such as inflammatory bowel disease. WO2011047328. The application generally states that preferably the polyclonal antibody composition is prepared by immunizing an animal with a target antigen, and the preferably the polyclonal antibody composition is derived from milk or colostrum with bovine colostrums being preferred (e.g., p. 14). The application also generally states that the animal derived polyclonal antibodies could be specific for (among other targets) other inflammatory cytokines (e.g., pp. 6-7). This application describes working examples in which cows were immunized with murine TNF and the colostrum was collected post-parturition to generate bovine polyclonal anti-TNF antibodies (designated as AVX-470). The uses of animal-derived antibodies and polyclonal antibodies, however, are undesirable.
IgA molecular forms have been proposed as treatments for various diseases, most notably as treatments for pollen allergies, as treatments against pathogens, and as treatments for cancer.
For example, two articles proposed the use of an anti-streptococcal antigen I/II secretory IgA-G hybrid antibody. Ma et al. “Generation and Assembly of Secretory Antibodies in Plants.” Science 268(5211), 716-719 (May 1995); Ma et al. “Characterization of a Recombinant Plant Monoclonal Secretory Antibody and Preventive Immunotherapy in Humans.” Nature Medicine 4(5); 601-606 (May 1998). The hybrid antibody contains murine monoclonal kappa light chain, hybrid Ig A-G heavy chain, murine J-Chain, and rabbit secretory component. The antibody was made by successive sexual crossing between four transgenic N. tabacum plants and filial recombinants to form plant cells that expressed all four protein chains simultaneously. The parent antibody (the source of the antigen binding regions, is identified as the IgG antibody Guy's 13. The group proposes that although sIgA may provide an advantage over IgG in the mucosal environment, such is not always the case (1998 Ma at p. 604, right column).
A related article identifies the anti-streptococcal antigen I/II secretory IgA-G hybrid antibody, which was derived from Guy's 13 IgA, as CaroRx. Wycoff. “Secretory IgA Antibodies from Plants.” Current Pharmaceutical Design 10(00); 1-9 (2004). Planet Biotechnology Inc. This related article states that the CaroRx antibody was designed to block adherence to teeth of the bacteria that causes cavities. Apparently, the CaroRx antibody was difficult to purify; the affinity of Protein A for the murine Ig domain was too low and protein G was necessary for sufficient affinity chromatography. Furthermore, the article states that several other chromatographic media had shown little potential as purification steps for the hybrid sIgA-G from tobacco leaf extracts. The article also indicates that the authors were unable to control for human-like glycosylation in tobacco, but that such was not a problem because people are exposed to plant glycans every day in food without ill effect.
WO9949024, which lists Wycoff as an inventor, Planet Biotechnology Inc. as the applicant, describes the use of the variable regions of Guy's 13 to make a secretory antibody from tobacco. The application contains only two examples—the first a working example and the second a prophetic example. Working Example 1 describes the transient production of an anti-S. mutans SA I/III (variable region from Guy's 13) in tobacco. The tobacco plant was transformed using particle bombardment of tobacco leaf disks. Transgenic plants were then screened by Western blot “to identify individual transformants expressing assembled human sIgA” (p. 25). Prophetic Example 2 states that in a transformation system for Lemna gibba (a monocot), bombardment of surface-sterilized leaf tissue with DNA-coated particles “is much the same as with” tobacco (a dicot). The prophetic example also stops at screening by immunoblot analysis for antibody chains and assembled sIgA, and states that the inventors “expect to find fully assembled sIgA.”
It is desirable to have alternative antibody treatments for TNFα-related inflammatory diseases that preferably avoid the disadvantages of current systemic and previously-proposed topical treatments of inflammation.